Net Force Zero for Constant Velocity

Steps:

• Boat moves at constant velocity, so acceleration is zero and net force equals zero by Newton's first law.
• Two tension forces act on the boat via the ropes; their vector sum is the total pulling force.
• A resistive force (e.g., water drag) opposes motion, so tensions' resultant must equal resistive force in magnitude but opposite in direction.
• Diagram shows tension vectors adding to this resultant, confirming balance.

Why A is correct:

• A states the resultant tension equals the resistive force, matching ΣF = 0 where pulling force balances opposition.

Why the others are wrong:

• B: Ignores resistance, implying unbalanced forces cause acceleration, violating constant velocity.
• C: Suggests tensions are equal and opposite, but diagram shows angled pulls with nonzero forward resultant.
• D: Claims zero resultant, but that would mean no motion against resistance.

Final answer: A